Police Themed DLC for GTA Online
Many fans would love to see a police-themed DLC added to GTA Online, in part because of the huge success of the LCPD mod for GTA IV (a similar mod for GTA V is also a highly popular idea). This sort of DLC would likely allow players to join an in-game police force.
For example, as suggested by some fans on Reddit recently, the player might first have to be accepted to the force by completing certain training missions. These missions would cover a variety of skills, so there would be driving missions, flying missions, and combat missions. A player accepted into the police force would then be given a squad car.
He or she would get into the car to activate police mode, which would come with restrictions: either it would be impossible to attack players that weren't engaged in criminal activities, or such actions would come with penalties and eventual expulsion from the police force.
Players who were performing criminal acts would be marked on the mini-map, and the player would join forces with NPC police to stop them, gaining access to a helicopter if the criminal's wanted rating hit 3 stars or higher. The only useable weapons in this DLC would be those used by the police and SWAT units—unless the situation required the player to seize the opponents' weapons in order to fight back.
Another possibility is that a cop NPC would always accompany the player on police missions, as an assistant, or two players could team up to play in co-op.
Whatever features it would include, police DLC would be well-received by a lot of fans. Similar ideas include firefighter DLC and paramedic/ambulance DLC, where the players would respond to emergency events across the city. If you'd like to see this sort of content added to GTA Online, be sure to contact Rockstar with your feedback—maybe it will become official DLC one day.